In recent years, with the development of an imaging technology, a projection lens for projecting has a wider and wider application range; and an interactive projection device has growing up gradually. In order to be suitable to the miniaturization of an electronic device and meet the interactive demands, it is required to ensure the projection lens miniaturization and sufficient field angle, as well as high imaging quality and being capable of acquiring information. A conventional projection lens for projecting, which is generally used for imaging, may encompass many lenses to eliminate various aberrations, improving resolution but resulting in an increasing length of the projection lens, which is adverse to miniaturization. Besides, a projection lens for projecting being of a large filed angle generally has serious distortion and low imaging quality.
The interactive device achieves an interactive function such as multi-point touch and gesture recognition mainly based on a process including: generating a signal through a projection lens for projecting; capturing an image by an imaging lens; and extracting information with image processing software. Accordingly, quality of the analog signal generated by the projection lens for projecting plays a critical role in extracting information with high precision. It is more easily to extract information under an infrared spectrum due to its characteristic per se, which may avoid adverse effects by filtering out visible light.
Therefore, the present disclosure provides in embodiments a projection lens, which may be used in the interactive device and applied under the infrared spectrum.